I. Field of the Invention
This invention relates to methods for preparing the compound hydrazodicarbonamide which has the formula ##STR3##
II. Description of the Prior Art
Hydrazodicarbonamide can be obtained by the known method of reacting urea and hydrazine sulfate in an acid medium (see for example, Kirk-Othermer Encyclopedia of Chemical Technology, 2nd Edition, Vol. II).
Hydrazodicarbonamide can also be obtained by reacting a 3,3-dialkyldiazacyclopropane with urea in the presence of sulfuric acid (Japanese patent application No. Sho-42-76931)
One method for preparing azines comprises the oxidation of ammonia in the presence of a ketone or aldehyde by means of an oxidizing medium comprising hydrogen peroxide and cyanogen or a nitrile. This method solely invented by the instant inventors is fully disclosed in commonly assigned pending U.S. patent application Ser. No. 152,413, filed June 11, 1971, now abandoned, which is incorporated by reference herein.
Another method for preparing azines comprises oxidizing a secondary alcohol in the liquid phase to form peroxide products of the auto-oxidation of the alcohol and subsequently reacting the peroxide products with ammonia in the presence of cyanogen or a nitrile. This method is fully disclosed in commonly assigned pending U.S. patent application Ser. No. 230,038, filed Feb. 28, 1972, now abandoned, which is also incorporated by reference herein.
The azines formed by each of these methods can be recovered employing various methods such as decantation, liquid-liquid extraction, distillation, and so forth. The azines can be utilized herein in either the substantially pure state or in aqueous or organic solution. If solutions of azines are used, they can also contain unreacted products from which the azines are derived, as for example, ketone or aldehyde in the event the method of Ser. No. 152,413, now abandoned, is employed.
The azines which are useful in the method of this invention can be prepared by any other known method, for example, by oxidizing NH.sub.3 with chlorine in the presence of a ketone as disclosed in U.S. Pat. No. 3,527,753 or by the addition of acetone to a solution of hydrazine according to the Raschig process.